1. Field of the Invention
The present invention generally relates to technology for a semiconductor device, and more particularly, to a start-up circuit included a constant current circuit.
This application is a counterpart of Japanese patent application, Serial Number 317913/2000, filed Oct. 18, 2000, the subject matter of which is incorporated herein by reference.
2. Description of the Related Art
A conventional semiconductor device is shown in FIG. 77 of U.S. Pat. No. 5,191,555. The conventional semiconductor device are comprised of a lot of circuit elements in order to supply a stable constant current.
Recently, the semiconductor device is demanded to be driven by low current, low voltage and fast speed. Also, the semiconductor device is demanded to be manufactured small.
However, the conventional semiconductor device can not satisfy above demands, because the conventional semiconductor device has a lot of circuit elements and a large-scale area for manufacturing the circuit elements.
It is an object of the present invention to provide a semiconductor device that may be driven by low current.
It is another object of the present invention to provide a semiconductor device that may be driven by low voltage.
It is still another object of the present invention to provide a semiconductor device that may be driven at fast speed.
It is further object of the present invention to provide a semiconductor device that may reduce circuit scale.
According to one aspect of the present invention, for achieving the above object, there is provided a semiconductor device, is provided with a first current mirror circuit which has an input terminal and an output terminal, a second current mirror circuit which has an input terminal and an output terminal, wherein the input terminal of the second current mirror circuit is coupled with the output terminal of the first current mirror circuit, wherein the output terminal of the second current mirror circuit is coupled with the input terminal of the first current mirror circuit, a start-up circuit which supplies current to the input terminal of the second current mirror circuit in accordance with voltage of the input terminal of the first current mirror circuit.
The above and further objects and novel features of the invention will more fully appear from the following detailed description, appended claims and the accompanying drawings.